APP and Alzheimer disease: The possible specific mechanisms for neuronal degeneration in AD may involve dysfunction of NMDA receptors [264,265], dysregulation of Ca2+ and mitochondrial homeostasis [266,267], defects in synapses [268,269,270,271,272], abnormalities in the metabolism of APP and presenilin proteins, toxic actions of Aβ protein derived from APP [273,274], and cytoskeletal pathology [275,276].